Sponge rubber-textile combination material



Sept. 18, 1951 E. B. LEWIS 2,567,951

' SPONGE RUBBER-TEXTILE COMBINATION MATERIAL Filed. April 7, 1948 ELISHA B- LEWIS RNEY Patented Sept. 18, 1951 SPONGE RUBBER-TEXTILE COMBINATION MATERIAL Elisha B. Lewis, Dayton, Ohio, assignor to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio Application April 7, 1948, Serial No. 19,568

3 Claims.

1 This application deals with a combined sponge rubber-textile material and a method of making it. The material of my invention has a great many uses as will be pointed out later, however. it is especially well suitable for floor coverings, such as rugs, carpeting and mats.

Floor covering material, especially when applied to hardwood floors, requires a padding in order to increase the grip of the carpeting with the floor and avoid that the floor covering becomes displaced. Such paddings have a number of disadvantages. During use, for instanc when being walked on, the padding becomes displaced and after a while shows at the edges which gives a very unneat appearance. Moreover, dirt accumulated in the floor covering material falls through its porous base so that, in removing all of the dirt, the floor coveringhas to be removed in order to have access to the padding. This is a very tedious procedure because any furniture on the carpets has to be taken off for this purpose.

It is an object of this invention to provide floor covering materials which are free from the disadvantages set forth above.

It is an object of this invention to provide a rubber-textile material which form one integral unit.

It is an object of this invention to provide a rubber-textile material in which the rubber covers the back of the textile material and penetrates and fills the interstices thereof without appearing on the face of the textile material.

It is another object of this inventon to provide a rubber-textile material which has a good gripping action so that it does not become dislocated during use.

It is another object of this invention to pro vide a rubber-textile material which has great softness and a high cushioning effect.

It is still another object of this invention tothe customary step of binding the edges with tape or the like may be dispensed with.

It is still another object of this invention to provide a rubber-textile material which is highly 2 flexible so that it may be rolled up for the purpose oi storage, shipping and the like.

It is still another objector this invention to provide a rubber-textile material which has sound-proofing characteristics.

It is still another object ofthis invention to provide a rubber-textile material which is flameresistant.

It is still another object of thisinvention to provide a floor covering material having a nap the fibers of which are firmly anchored to the base which is responsible for a long service life.

It is still another object of this invention to provide floor covering material having a nap which always reassumes its upright position whereby its newappearance is retained.

It is still another object of this invention to provide floor covering materials on which furniture, when moved, does not leave permanent marks.

It is still another object of this invention to provide floor covering materials in which, when made of a plurality of strips, the seams are practically invisible on the face of the floor covering.

These and other objects are accomplished by introducing 'nitrous oxide gas into a mixture of rubber'latex and sodium silicate solution while subjecting said mixture to high-speed agitation whereby a rubber foam is produced, thereafter depositing said rubber foam still in fluid form on the back of the textile material to be treated and finally curing said foam on said textil ma-- terial.

The process of my invention may be carried out in a continuous as well as a discontinuous operation. An apparatus suitable for manufacturing the material of this invention is described in detail in my co-pending application Serial No. 13,605 filed March 8, 1948, entitled Method of Making Sponge Rubber (now abandoned).

While the quantity of sodium silicate may vary within wide ranges, it has been found that particularly good results are obtained with a proportion of substantially 2.25 per cent by volume of sodium silicate solution with regard to the latex. It has also been found that while nitrous oxide gas may be introduced under pressure, the use of high speed stirring is superior thereto, because substitution of agitation for pressure makes possible simplification of the process as well as of the apparatus for carrying out the process.

While most kinds of synthetic and natural latices are satisfactorily operative for the proc-- cos of m invention. it has been found that neoprene latex yields the very best results.

The addition of sodium silicate makes refrigeration of the latices unnecessary, since it prevents coagulation and acts as a curing decelerator. A quantity of 20 per cent sodium silicate by volume for example, was used in one instance in order to dispense with refrigeration; however, 2.25 per cent .by volume with regard to the latex yield the same favorable effect and in addition thereto have the advantage of producing a still higher volume increase than was obtained with 20 per cent by volume of the agent. This finding was quite unexpected and contrary to logical reasoning.

The sodium silicate solution preferably used has a density of 41 B. and a molar ratio of alkali to silica of l to 3.22. The latices are advantageously employed in a concentration of or about 50 per cent.

High speed stirring may either be carried out by employing a simple stirrer and moving it upand down during operation so as to cause agitation in all layers or levels of the liquid, or else a so-called compound stirrer, which is one having a plurality of blades or vanes at its axle shaft, may be used. A speed of up to 5,000 R. P. M. has proven suitable.

It will also be satisfactor to combine the high speed agitation with the application of pressure. By this a still greater volume increase is obtained; however, since the application of pressure complicates the apparatus, it is a question of economy as to whether it is preferable to sacrifice a certain degree of porosity for the advantage of lower cost or whether to produce with the highest efficiency disregarding the cost of production.

After the foam has bee prepared it is deposited while still in fluid condition onto the back of the textile material. Thereafter the combination is cured; while curing may be carried out in an oven, the use of infra-red light has been found preferable. Exposure for a time of from 15 to 20 minutes gave satisfactory results. If a backing of considerable thickness, for instance of 1" and more, is to be applied, it was found advisable to prepare, deposit and cure the foam in installments. This is carried out by first depositing a foam layer of, say thickness, heating for 15 to 20 minutes, superposing another foam layer of about the same thickness and ouring the added layer. These steps are repeated until a product of the desired thickness is obtained. The sponge produced by this stepwise procedure does not show any lines of separation; it is an integral unit and has the same excellent qualities as sponge produced by the one-step process.

For the vulcanization with infra-red light, a voltage of 115 volts and 375-watt lamps were used. The distance of the lamps from the rubber surface was approximately 16".

Another very satisfactory modification of carrying out infra-red heating, it has been found, is first to use a voltage of 110 volts for approximately minutes and thereafter 220 volts for another minutes.

In some cases the increase of volume durin the foaming step was so great, that the cell walls tended to or did collapse.- In order to prevent this failure and to strengthen the cell walls from 3 to 5 per cent by volume of high volume of highalpha-cellulose was added to the latex.

In the following, an example is given of a latex composition whichwas found particularly advantageous for the production of combined sponge rubber-textile material by the process of my invention. This example, it will be understood, is given merely for the purpose of illustration but not for, that of limitation.

The ingredients are added in the. order given above under rapid agitation with a compound stirrer. After the light viscosity vegetable oil is added, nitrous oxide is introduced; the mixture is foamed thereby and its volume increased by about 450%. Thereafter the sodium silico-fiuoride dissolved in approximately 50 cc. water is added while still continuing the stirring operation. From the foam thus obtained, a A" thick layer is poured onto the back of the textile material, and the assembly is then cured under infrared light for approximately 15 minutes. Thereafter, another layer is superposed and again ouring carried out for the same time and under the same conditions as in the first step.

The product obtained has a sponge rubber backing of low density, a fine porous structure and high resiliency; no separation lines are visible in the sponge rubber where the second and first sponge rubber layers contact.

It will be understood that the latex compositions used for the process of my invention may contain other additional ingredients than those mentioned in the example given. For instance, latices containing accelerators, vulcanizing agents and other auxiliary materials customary and well known to those skilled in the art are withinthe scope of my invention. Likewise, the compositions of the latex and the curing conditions may be chosen so as to obtain a final product of the desired degree of hardness.

It will be also understood that the term textile materials" comprises not only woven fabrics,

since the invention is equally well applicable to matted materials. If a completely non-inflammable material is desirable, glass fibers, either matted or woven, are advantageous. Such glass fibers-sponge rubber combination is also satisfactory as heat insulating material.

One of the prime advantages obtained with the rubber foam made according to the invention is that a non-inflammable product is obtained. The sponge rubber also makes the material soundproof which is especially valuable in the case of carpeting material and portieres. Since the sponge rubber is integrally united with the textile material and, in the case of carpeting, the nap is securely anchored bythe sponge rubber, an excellently durable floor covering is obtained. The interstices of the textile material being filled with rubber, the dust accumulated in the covering cannot fall through so that lifting of the carpeting is not necessary for cleaning urposes. The nap always retains its upright position due to the resiliency of the rubber material. Floors covered with the material of this invention are not as tiring to one walking thereon as are other floors having the conventional carpeting in view of the high cushioning eflect and resiliency of the sponge rubber. No dislocation of a separate pad occurs which is another advantage of the article of my invention. Furniture, which usually makes'deep' and permanent impressions in carpeting material so that the marks remain and spoil the appearance of the carpet when that furniture is moved, does not have any permanent effect on the carpeting of the invention, no matter how heavy the furniture is. The rubber provides for such a high degree of resiliency that the original appearance is always resumed shortly after impressions have been made on the nap.

Whereas carpeting when cut to size has to be bound at the edges by means of tape in order to avoid fraying, the material of my invention does not require such treatment of the edges since the fibers, including the nap, are firmly anchored by the rubber layer.

In the accompanying drawings, some embodiments .of the products of the invention are diagrammatically illustrated.

Figure 1 is a plan view of a fabric used for the process of my invention;

Figure 2 is a cross sectional view taken along line 2.2 of Figure 1 showing the structure of the finished product;

Figure 3 is a plan view of a carpeting composed of three strips; and

Figure 4 is a cross sectional view taken along line 4- of Figure 3.

Referring to the drawings, in particular the reference numeral l designates warp threads of a. fabric and H its filler threads. In Figure 2, nap fibers l2 which extend from said fabric are visible. A layer of sponge rubber I3 is applied to the back of said fabric and it may be readily seen that the sponge rubber penetrates the interstices of the fabric and thereby anchors the nap firmly to the fabric. The sponge rubber has a great number of. uniformly distributed discrete cells ll.

Figure 3 illustrates a carpeting piece I5 composed of three strips I6, I! and Ill. The strips are sewn together at the seams l9 and 20. A sponge rubber layer 2| has been applied to said combined carpeting material. It will be seen from Figure 4 that this sponge rubber not only penetrates the interstices of the fabric but also the seams l9 and and thereby anchors the strips and combines them into one integral unit. The nap layer 22 of the carpeting material l5 does not show any irregularity or spacing above the seams l9 and 20 so that the carpeting has the appearance of one single piece.

The material of the invention lends itself to a great many applications. It has been used with great satisfaction for rugs, carpeting, floor mats, draperies, portieres, chair cushions, and upholstering material. Other uses may be found once the excellent qualities and characteristics of the material of the invention have become known.

It will be understood that while there have been disclosed herein certain specific embodiments of my invention it is not intended thereby to have the invention limited to the details given in view of the fact that it is susceptible to various modifications and changes which come within the spirit of the" disclosure and the scope of the appended claims.

I claim:

1. A combination material consisting of a textile layer and a fire resistant layer of vulcanized sponge rubber which contains sodium silicate, said textile material having a napped surface and said sponge rubber penetrating the interstices of said textile layer and firmly anchoring the threads of said nap.

2. A fire resistant material consisting of a layer of glass fibrous material and a vulcanized sponge layer of a neoprene rubber-sodium silicate mixture interstitially united with said glass material.

3. A fire resistant floor covering material combined of a plurality of textile strips and a vulcanized unitary sponge layer of a rubber-sodium silicate mixture, said layer uniting said strips and filling the interstices of said textile material.

ELISHA B. LEWIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,845,688 Untiedt Feb. 16, 1932 2,069,753 Emhardt Feb. 9, 1937 2,092,825 Behr Sept. 14, 1937 2,126,273 Ogilby Aug. 9, 1938 2,129,622 Manchester Sept. 6, 1938 2,163,289 Pennell et al June 20, 1939 2,187,140 Faris et a1 Jan. 16, 1940 2,239,457 Gibbons Apr. 22, 1941 2,288,190 Harrison June 30, 1942 2,321,111 Stamberger June 8, 1943 2,444,546 Walsh July 6, 1948 

1. A COMBINATION MATERIAL CONSISTING OF A TEXTILE LAYER AND A FIRE RESISTANT LAYER OF VULCANIZED SPONGE RUBBER WHICH CONTAINS SODIUM SILICATE, SAID TEXTILE MATERIAL HAVING A NAPPED SURFACE AND SAID SPONGE RUBBER PENETRATING THE INTERSTICES OF SAID TEXTILE LAYER AND FIRMLY ANCHORING THE THREADS OF SAID NAP. 